The invention relates to a pneumatically powered apparatus for removing roofing material from a roof, in particular asphalt shingles, felt, and tar paper nailed to a pitched wooden deck.
Roofers generally use hand tools such as shovels and pry bars to remove roofing material. Specialized hand tools have been developed. See, for example, U.S. Pat. No. 5,280,676. However, any manual process is physically exhausting and time consuming, regardless of the tool used. As such, efforts have been made to develop an automated device, and some have been patented.
U.S. Pat. No. 4,269,450 discloses an apparatus having a rotary cutter head driven by an electric motor. As such it is heavy and requires a source of AC current.
U.S. Pat. No. 4,277,104 discloses a gasoline engine driven shingle remover with a flywheel and a system of links used to lift a plate which removes the shingles.
U.S. Pat. No. 4,709,479 discloses an apparatus which utilizes a vertically mounted pneumatic cylinder which pulls the rear end of a lever member downward in order to move a blade at the opposite end through an elliptical path of movement. Intermediate the two ends is a complex series of links, cranks, and ratchets which also cause the apparatus to move forward as the blade is lifted.
U.S. Pat. No. 4,763,547 discloses an apparatus wherein a lift plate is driven by a pneumatic cylinder directly; there is no intermediate lever member for obtaining mechanical advantage. The apparatus is simple but appears to require a manual assist.
U.S. Pat. No. 4,880,491 discloses an apparatus using an electric motor and a series of belts and links to lift a shingle removing plate. The apparatus is relatively cumbersome, and requires cables and a drive track to stabilize it on a roof. However, the patent offers a detailed discussion of the prior art and its disadvantages. Gasoline engines are considered unsuitable due to the fuel hazard, the noise, and the need to keep the carburetor floats level. Top heavy devices tend to topple over and fall off the roof.